The question that always comes back
"Can I put a Shimano cassette with a SRAM derailleur?" It's probably the most-asked compatibility question in bike mechanics. The short answer: it depends. The long answer is this article.
The key concept: pull ratio
The pull ratio (or cable pull ratio) is the amount of cable pulled by the shifter to move the derailleur one click. It's the determining factor for compatibility between shifters and derailleurs.
- Road mechanical: SRAM and Shimano use the same pull ratio in 10 and 11 speed. You can mix shifters and derailleurs without issue
- MTB mechanical: SRAM and Shimano use different pull ratios. A Shimano shifter won't correctly drive a SRAM derailleur, and vice versa. Indexing will be off
Notable exception: some third-party adapters (like Jtek ShiftMate) modify the pull ratio to make the incompatible compatible. It works, but adds a part and friction.
Cassettes: good news
Shimano HG (HyperGlide) cassettes and SRAM cassettes on HG freehub bodies are interchangeable. The spline standard is the same. You can mount:
- A SRAM cassette on a Shimano HG freehub body
- A Shimano cassette on a SRAM freehub body (HG compatible)
Watch out for exceptions:
- Shimano Micro Spline (12-speed road and MTB): specific freehub body, incompatible with SRAM cassettes
- SRAM XD / XDR: specific freehub body, incompatible with Shimano cassettes
- 12-speed cassettes from each brand require their own freehub body
Chains: broad compatibility
Chains are the most interchangeable component:
- 9-speed: Shimano, SRAM, KMC — all cross-compatible
- 10-speed: same, full compatibility
- 11-speed: same, full compatibility
- 12-speed: it gets complicated. SRAM 12-speed chains (Flat Top) have a different profile from Shimano 12-speed chains. Theoretically incompatible, in practice some mechanics mix them without issues... but manufacturers don't recommend it
Advice: to be safe, use a chain from the same brand as your cassette. Otherwise, KMC makes chains compatible with both systems in 9-11 speed.
